Movable carriage assembly and ink ribbon control

ABSTRACT

A movable carriage assembly especially suitable for a mosaic printing head with means for moving the ink ribbon including a wind-up spool, a wind-off spool, and a gear unit that is coupled with a stationary element and which moves the ink ribbon spools by moving the carrier assembly.

ilited Etates atent [191 usciimann et a1.

' Oct. 15, 1974 MOVABLE CARRIAGE ASSEMBLY AND HNK RIBON CONTROL [75] Inventors: Hans Buschmann,

Bensberg-Refrath; Erwin Mellilliart, Porz-Urbach', Emil Pomplun, Steinenbruck; Alired Schwibbe, Cologne, all of Germany [73] Assignee: Nixdori Computer AG, Paderborn,

Germany 221 Filed: Apr.19,1972

21 Appl.No.:245,504

[30] Foreign Application Priority Data Mar. 24, 1972 Germany 2119414 [52] US. Cl 197/161, 197/158, 197/151 [51] int. (11 341i 33/44 [58] Field of Search 197/151, 153 R, 153 A,

[56] References Cited UNITED STATES PATENTS 481,750 8/1892 Diss 197/167 941,130 11/1909 1,087,990 2/1914 1,303,159 5/1919 1,800,399 4/1931 1,929,448 10/1933 1,949,107 2/1934 Mosfelt et al. 3,026,987 3/1962 Gather i 197/153 R 3,139,964 7/1964 Fischer 197/157 3,207,284 9/1965 Pateman et al. 197/151 3,340,989 9/1967 Busch 101/336 X 3,584,722 6/1971 Albrile 197/159 X Primary Examiner-Ernest T. Wright, Jr. Attorney, Agent, or Firm-Hauke, Gifford, Patalidis & Dumont [5 7 ABSTRACT A movable carriage assembly especially suitable for a mosaic printing head with means for moving the ink ribbon including a wind-up spool, a wind-off spool,

and a gear unit that is coupled with a stationary element and which moves the ink ribbon spools by moving the carrier assembly.

6 Claims, 4 Drawing Figures PAIENTED [JET l 5 I974 SHEET 2 OF 2 2v INK BACKGROUND OF THE INVENTION I. Field of the Invention The present invention is directed to mosaic printing heads and more particularly to means for moving the ink ribbon for such heads.

II. Description of the Prior Art Mosaic printing heads which operate according to the principle of needle printing are well known. A needle printer having a long needle path to thereby provide a large recording width and the possibility of utilizing both recording directions necessitates a specially designed ink ribbon arrangement which guarantees uniform, non-jerky ribbon movement without the ribbon sagging, with free-of-stress reversal of the direction in which the ink ribbon moves, and optimal utilization of the stored ink whereby maximum life of the ink ribbon can be achieved. Furthermore, very fast color change, e.g., from black to red, or fast removal of the ink ribbon from the writing area should be possible in order that the respective written symbols can be viewed, for example, when writing is interrupted.

SUMMARY OF THE PRESENT INVENTION An object of the present invention is to provide a carriage assembly which fulfills the above-indicated requirements and which is distinguished by the reliable method of its operation.

To fulfill this task, a carriage assembly of the abovenamed type is, according to the invention, characterized in that in both directions of motion of the carriage assembly, a gear unit contains elements rotating in the same direction and which move the ink ribbon spools in the same direction and that at least one boss of the ink ribbon spool is provided with an eccentric element, upon rotation of which an engaging lever causes a continuous up-and-down movement of the ink ribbon.

This continuous up-and-down movement of the ink ribbon provides uniform wear so that optimal utilization of the ink stored in the ribbon is possible. Furthermore, the elements rotate in the same direction independently of the direction in which the carriage assembly moves, hence, uniform and non-jerky transport of the ribbon spools is assured independently of a change of the direction in which the carriage assembly moves.

The engaging lever is adjustable to different initial positions which correspond to selective operational positions of the ink ribbon with different guide heights and even to a complete removal of the ink ribbon from the writing area. This makes it possible to bring multicolored ribbons to the standard guide height for a certain color and in addition, to cause complete clearing of the writing area so that during interruptions of the writing, the graphics produced can be also inspected where the carriage assembly has just been stopped.

In order to make possible the continuous up-anddown movement of the ink ribbon starting from the respective adjusted initial position, it is advantageous that at least one boss of the ink ribbon spool has an eccentric circumference and that on the ribbon spool boss, there is mounted the engaging lever designed as a bell crank lever and having a recess fitted to the eccentric circumference. The rotation of the ribbon spool boss,

because of the eccentricity provided, continuously produces reciprocating motion of the engaging lever, which results in a corresponding horizontal swing of its arm and which is readily transferable to the guiding of the ink ribbon when suitable gearing is used.

With respect to the elements rotating in the same sense in both directions of motion, the carriage assembly is designed so that each ribbon spool boss is pro vided with a pinion which is coordinated with one of two intermeshed coupling gears which are supported between both pinions in a common plane, which are jointly disposed on a slide bar making possible coupling with one pinion at a given time, and which moreover are geared each time with a gear wheel connected with one pinion via a freewheel clutch. Furthermore, the carriage assembly is so designed tha the freewheel clutches provide freewheeling in opposite directions of motions of the pinions which are coupled with the stationary element.

In this manner, the total gear unit can be designed very simply and save space, for altogether, only four additional pivots are required for the additional wheels provided between the pinions driving the ink ribbon spools. Coupling between the ribbon spools for reversal of the direction of motion is not necessary. As will be shown further on, appropriate fixing of both possible positions of the slide bar results in its automatic sliding motion because the carriage assembly moves at freely chosen moments, thus making it possible that the direction of transport of the ink ribbon is reversed in a nonjerky manner. The sliding motion is automatic because the coupling gear wheel functioning in the respective case is mounted on a sliding element, hence, when driven by a pinion, it is first of all so far moved before coupling that it can transfer its rotary motion to one of the pinions driving the ribbon spools, if necessary, via the other coupling gear wheel with which it is geared.

DESCRIPTION OF THE DRAWING Further characteristics and refinements of the invention are subsequently described with the aid of the drawing which depicts a specific embodiment of the present invention.

In detail,

FIG. 1 shows a top plan view of a carriage assembly according to the invention;

FIG. 2 shows a view of a part of the carriage assembly in the direction of view ll depicted in FIG. I;

FIG. 3 shows the carriage assembly depicted in FIG. 2 in the top plan view Ill; and

FIG. 4 shows the mechanism for lifting and lowering of the ink ribbon.

DESCRIPTION OF A PREFERRED EMBODIMENT The carriage assembly in FIGS. 1, 2 and 3 is shown without the mechanism for lifting and lowering the ink ribbon for purposes of clarity and to facilitate understanding of the invention.

FIG. 1 depicts a plate bar 32 as part of a frame 3 which is movable with a printing head 6 (FIG. 4), for example, on slides 4 (only partially shown for clarity) by a slide tab 5 which is integral with or fastened to the frame 3. The means for moving the carriage assembly along the slides 4 may comprise, for example, a pulley driven by an'electric motor 102 which is secured to the stationary frame of the mosaic printer 104 (shown in schematic only). A pair of pulleys 106 are rotatably connected to the frame of the printer I04 and a length of wire, string, or the like, I03 is wound around the the three pulleys I06 and 160 and the free ends of the wire 108 are connected to outwardly extending tabs III) of the frame 3. Thus as the motor 162 rotates pulley I00, the carriage assembly moves along slides 4. To plate bar 32, there are also attached bearing bolts and 25a on which bosses 26 and 26a are eccentrically mounted. In each case, the bosses 26 and 26a respectively support a driving pin 27 or 27a for rotating ink ribbon spools 112 (FIG. 4 only one shown)) which are not shown in FIG. I. The bosses 26 and 26a are respectively fixed to rotate with the gear wheels 23 and 23a. The gear wheels 28 and 28a can be coupled with gear wheels 29 and 29a respectively which pivot on pins 30 and 36a of a slide bar 31 and which are in gear with each other. Depending upon the position of the slide bar 3ll, the gear wheels 28, 29 or the gear wheels 28a, 29a can be coupled with each other. The slide bar 31, which by means of guiding pins 33 can. slide in elongated slots 34 of plate bar 32, is illustrated in FIG. I as locked in its left end position. In this position, there is situated a lug 35 of a locking lever 36 which pivots on a pin 37 on the plate bar 32 and which behind a shoulder 39 of the slide bar 31, is lightly tensioned by a spring 33. similar means with the corresponding parts 350 to 39a is situated on the opposite end of the assembly, except that there, the lug 35a lies onshoulder 39a and in this position does not exert a locking effect on slide bar 31.

Ink-ribbon brake levers 4t) and 400 having arms 43 and 43a, respectively, are swivel-mounted on the frame 3 pivoting on bearing bolts 41 and 41a respectively and exert such an effect on the locking levers 36 and 36a that when the ribbon brake levers and 46a are horizontally moving in the tensioning direction of stronger springs 42 and 42a, the arms 43 and 43a of the brake levers 40 and 40a hit legs 44 and 44a of locking levers 36 and 36a and swing them horizontally against the tension of the weaker springs 38 and 38a and thereby release the locking if it is in effect. The brake levers 40 and 40a are preferably of one-piece construction with their respective amrs 43 and 43a. In the preferred embodiment a bar portion 120 or I20a extends between the brake lever 40 or 40a and its arm 43 or 43a and is integral therewith to fixedly connect the brake lever 40 or 400 to its respective arm 43 or 43a.

The position of the ribbon brake levers 4t) and 40a is determined as is known by the amount of ink ribbon 62 (FIG. 4) present on the respective ribbon spool I12 (FIG. 4). The above-described unlocking of slide bar 31 starts when the ribbon spool lll2 (FIG. 4) being wound off contains only a small safety residue of ink ribbon 62 (FIG. 4).

As best seen in FIGS. 2 and 3, the plate bar 32 furthermore contains stationary pins 45 on which the bosses 47 of gear wheels 46a and 46 pivot, as shown in cross section in FIG. 2. A freewheel clutch connects pulleys 48 and 48a with the bosses 47 in such a manner that when pulleys 48 and 48a rotate in the direction indicated by arrows (FIG. 3), they carry along the respective gear wheel 46 and 46a connected thereto while rotation of pulleys 48 and 48a in each opposite direction of rotation results in slight braking between pulleys 48 and 48a and their respective gear wheels 46 and 46a. The freewheel clutches consist, for example, of torsion springs 116 (FIG. 2) having opposite winding directions. Hence, when the pulleys 48 and 48a are rotated in the winding direction of the respective torsion spring I16, the corresponding gear wheel 46 and 46a is carried along. This can be best seen from the graphical representation in FIG. 3. The freewheel clutch 49 cooperating with pulley 48 is depicted in cross section in FIG. 2 and by a top plan view in FIG. 3.

The driving element for the pulleys 48 and 48a is, for example, a flexible member 50 which is so wound around the pulleys 48 and 48a that upon lateral movement (FIG. I) of the plate bar 32, both pulleys 48 and 48a are rotated in the same direction. The ends of the member 50 are fastened to a bedplate 75 on the stationary frame of the mosaic printer 104. Of course, the pulleys 48 and 48a could alternately be designed as gear wheels which cooperate with a cog rack thus eliminating the need for flexible member 50.

FIG. 4 shows the mechanism for lifting the ink ribbon 62. FIG. 4 depicts the boss 26 with the driving pin 27 which pivots relative to its bearing bolt 25 or axis of rotation with an concentric boring. On the boss 26, there is mounted a bell crank lever 51 with its boring 52, having an arm 53 which is connected with a draw rod 54 of a stationary electromagnet 55 while another arm 56 is connected with an ink ribbon fork 57. For this purpose, angular edge 58 of arm 56 hits arm 59 of ribbon fork 57 and thus swings the fork 57 in a vertical plane about its pivot 60 against the tension of a spring 6I whereby the ink ribbon 62 changes its height level.

The conveying of the ink ribbon 62, the reversal of the direction of movement, the lifting and lowering of the ink ribbon 62 for its better utilization and for ribbon change take place in the following manner.

When the frame 3 of the printing head 6 (FIG. 4) and therewith, plate bar 32 slides to the left (FIG. 3), for example, on slides 4 (FIG. 1), the pulleys 48 and 48a are rotated clockwise (FIG. I) by the member 50 (FIG. 3). The pulley 43a thus does not exert any effect on the other gear wheels 23, 29a, 28 or 28a since its freewheel clutch prevents carrying along the gear wheel 46a, however, gear wheel 46 is carried along by pulley 48. By automatic shifting of the slide bar 31 via the gear wheels 29 and 290 into the configurment shown in FIG. I, gear wheel 46 transfers its motion to the gear wheel 28a and rotates it counterclockwise whereby the ink ribbon 62 is wound on the left ribbon spool I12 (FIG. 4) as viewed in FIG. I.

The gear wheel 28 is not connected to gear wheel 29, hence, the ink ribbon 62 can be wound off the right rib bon spool H2 (FIG. 4) whereby the ribbon brake lever 40 effects slight braking in the known manner.

However, when the frame 3 slides to the right (FIG. 3), the sense of rotation of pulleys 48 and 48a is re versed to a counterclockwise direction (FIG. I) whereby the pulley 48a is coupled with the gear wheel 46a and the latter moves the gear wheel 28a counterclockwise via the gear wheel 29a. This takes place because of the continued effective locking of slide bar 31 in its left end position (FIG. I), which has been already described. Thus, the ink ribbon 62 continues to be wound on the left spool 112 (FIG. 4). Then, free wheeling exists between the pulley 48 and the gear wheel 46 because of the released freewheel clutch 49.

When the ink ribbon 62 has been wound off the right ribbon spool 112 (FIG. 4) to such an extent that the arm 43 of the ribbon brake lever 40 lifts the locking lever 36 with its lug 35 from the locking position at the slide bar 31 and when the gear wheel 86a rotates counterclockwise because the frame 3 correspondingly moves to the right (FIG. 1), the slider bar 31 together with the gear wheels 29 and 29a is shifted to the right by the disengagement of the freewheel clutch 49; consequently, gear wheel 29 engages with the gear wheel 28 and reverses the transport direction of ink ribbon 62. Then, the brake lever 36a with its lug 35a has placed itself behind the shoulder 39a of the slide bar 31 and therewith has locked the latter in that position.

The rotation of the eccentric boss 26 (FIG. 4) imparts an oscillating motion to the angle lever 51. Since the latters arm 53 is prevented from freewheeling by the draw rod 54 of the electromagnet 55, the effect of the motion on arm 56 of the angle lever 51 consists in ribbon fork 57 moving the ribbon 62 up-and-down in a rhythm corresponding to the rotation of boss 26 and in extending the up-and-down movement so far that during continuous printing, the area of the ink ribbon 62 used is greater than that required by the respective height level of the character. It the electromagnet 55 is switched on, the draw rod 54 is pulled in to a fixed extent, and the pivotal point between the draw rod 54 and arm 53 is shifted whereby the ribbon fork 57 is lifted so far that another color area, for example, red comes into writing position. The previously described action of lifting and lowering of the ink ribbon 62 remains preserved within the color area chosen in this manner.

When the electromagnet 55 has different switch positions or is fed by a different amperage, the ribbon fork 57 can be brought into such an elevated position that it clears the view on the writing area.

We claim:

1. An assembly for mounting an ink ribbon for use with mosaic printing devices and the like, said assembly comprising:

a bar member and a pair of ink ribbon spools rotatably mounted on said bar member in spaced positions;

an ink ribbon mounted on said spools such that rotation of one of said spools in one direction rolls said ribbon onto said one spool and rotation of the other spool in an opposite direction rotates said ribbon onto said other spool,

means reciprocably moving said bar member in a longitudinal direction,

gear means operable when coupled to said spools to rotate said spools in a direction winding said ribbon onto a driven spool,

means converting movement of said bar member to movement of said gear means,

means sensing the depth of the ribbon wound onto one of said spools and engaging said gear means to 6 the other of said spools such that the direction of movement of said gear means is independent of the movement of said bar member,

a slide member slidably mounted with respect to said bar member and in which said gear means comprises:

a first pair of gear members mounted to said slide member in meshing engagement with each other; and

a second pair of gear embers with one of said second pair of gear members carried respectively by each of said spools, a different one of said second pair of gear members being in engagement with said first pair of gear members at each spaced position of said slide member whereby one of said spools is respectively driven by said first set of gear members at each position of said slide member.

2. The assembly as defined in claim 1 and in which said gear means further includes:

a third pair of gear members rotatable in a direction which depends upon movement of said bar member and means translating movement between said third pair of gear members and said first pair of gear members in the same direction regardless of the direction of movement of said bar member.

3. The assembly as defined in claim 2 and in which said translating means comprises a free wheel clutch means connected to said third pair of gear members with one of said third pair of gear members being free wheeling in one direction and the other of said third pair of gear members being free wheeling in an opposite direction whereby one of said third pair of gear members drives said first pair of gear members at a time and in the same direction regardless of the direction of movement of said bar member.

4. The assembly as defined in claim 1 and in which said sensing means comprises a lever pivotal, upon the ribbon on one of said spools reaching a predetermined circumference, to release said slide member for sliding movement in the opposite direction to engage said first pair of gear members with the gear member carried by the opposite spool.

5. The assembly as defined in claim 4 and including means locking said slide member in each of said spaced positions.

6. The assembly as defined in claim 1 and in which the slide member is provided with shoulders on opposite edges and including a pair of locking levers carried by said bar member, said locking levers each having a lug to engage said shoulders of said slide member to lock said slide member in one of said spaced positions, and means for unlocking one of said locking levers upon movement of said slide member away from one of said spools. 

1. An assembly for mounting an ink ribbon for use with mosaic printing devices and the like, said assembly comprising: a bar member and a pair of ink ribbon spools rotatably mounted on said bar member in spaced positions; an ink ribbon mounted on said spools such that rotation of one of said spools in one direction rolls said ribbon onto said one spool and rotation of the other spool in an opposite direction rotates said ribbon onto said other spool, means reciprocably moving said bar member in a longitudinal direction, gear means operable when coupled to said spools to rotate said spools in a direction winding said ribbon onto a driven spool, means converting movement of said bar member to movement of said gear means, means sensing the depth of the ribbon wound onto one of said spools and engaging said gear means to the other of said spools such that the direction of movement of said gear means is independent of the movement of said bar member, a slide member slidably mounted with respect to said bar member and in which said gear means comprises: a first pair of gear members mounted to said slide member in meshing engagement with each other; and a second pair of gear embers with one of said second pair of gear members carried respectively by each of said spools, a different one of said second pair of gear members being in engagement with said first pair of gear members at each spaced position of said slide member whereby one of said spools is respectively driven by said first set of gear members at each position of said slide member.
 2. The assembly as defined in claim 1 and in which said gear means further includes: a third pair of gear members rotatable in a direction which depends upon movement of said bar member and means translating movement between said third pair of gear members and said first pair of gear members in the same direction regardless of the direction of movement of said bar member.
 3. The assembly as defined in claim 2 and in which said translating means comprises a free wheel clutch means connected to said third pair of gear members with one of said third pair of gear members being free wheeling in one direction and the other of said third pair of gear members being free wheeling in an opposite direction whereby one of said third pair of gear members drives said first pair of gear members at a time and in the same direction regardless of the direction of movement of said bar member.
 4. The assembly as defined in claim 1 and in which said sensing means comprises a lever pivotal, upon the ribbon on one of said spools reaching a predetermined circumference, to release said slide member for sliding movement in the opposite direction to engage said first pair of gear members with the gear member carried by the opposite spool.
 5. The assembly as defined in claim 4 and including means locking said slide member in each of said spaced positions.
 6. The assembly as defined in claim 1 and in which the slide member is provided with shoulders on opposite edges and including a pair of locking levers carried by said bar member, said locking levers each having a lug to engage said shoulders of said slide member to lock said slide member in one of said spaced positions, and means for unlocking one of said locking levers upon movement of said slide member away from one of said spools. 